Inorg. Chem. zyxwvu 1985, zyxwvu 24, zyxwvut 1379-1383 1379 complexes and has pointed out that the latter is a very sensitive function of bond angle. In the above-mentioned Fez compounds, a variation of bond angle of only -6O gave a chemical shift variation of 80 ppm.’” We have structurally characterized several (CO),W(p-PPh,),ML, comple~es~~*~~*~~.’~ and have tried to correlate structural results to 31P NMR chemical shift data for these compounds. However, zyxwvutsr no obviqus correlation exists among the metal-metal distances, M-P-M angles, and zyxwvutsrq 31P NMR data, as illustrated in Table V. This result is perhaps not too surprising since the metal-ligand combinations employed in the metal fragment linked to the (CO),W(r-PPh,), unit vary considerably. However, these data do point out serious problems in employing the p-PRz chemical shift/metal-metal bond ~orre1ation.l~ The correlation appears to be best used for closely related series of compounds in which one or more members have been structurally characterized. Stability and Reactivity of Complexes 1-4. Complexes 1-3 are stable in air for zyxwvutsrqpo - 1 week in the solid state before showing signs of decomposition. However, solutions of the complexes decompose (15) Rosenberg, S.; Geoffroy, G. L.; Rheingold, A. L., to be submitted for publication. (16) Mercer, W. C.; Geoffroy, G. L.; Rheingold, A. L. Organometallics, in press. (17) In this paper the periodic group notation is in accord with rccent actions by IUPAC and ACS nomenclature committees. A and B notation is eliminated because of wide confusion. Groups IA and IIA become groups 1 and 2. The d-transition elements comprise groups 3 through 12, and the pblock elementscomprise group 13 through 18. (Note that the former Roman number designation is preserved in the last digit of the new numbering: e.&, 111 - 3 and 13.) within minutes following air exposure. Complex 4, although never obtained pure, is more air sensitive than 1-3. The reactivities of complexes 1 and 2 were briefly explored with Li[BHEt3], CH3Li, BuLi, and PhLi in attempts to form formyl and acyl derivatives in which these ligands could perhaps be stabilized by bridging between the metals, presumably with oxygen bound to the oxo- philic Zr center. However, in no zyxw case were stable products isolated. Infrared monitoring showed that no reaction occurred when 1 and 2 were allowed to react with Li[BHEt3] and CH3Li. Reaction of these complexes with PhLi at -78 OC did yield new vco bands at lower energy (e.g., 1 + PhLi - bands at 1925, 1850, 1840 cm-’) but all workup attempts led to decomposition of the product(s) formed. Also, infrared monitoring revealed that no reaction occurred when complexes 1 and 2 were heated (70 “C) or irra- diated (>300 nm) in the presence of PhCECPh, PMePh2, and Acknowledgment. We thank the National Science Foundation (Grant CHE8201160) for support of this research, the Sohio Corp. for fellowship support, and Dr. T. Baker (Du Pont) for commu- nication of unpublished results. Registry No. 1,95465-26-2; lC6H,403, 95465-28-4; 2a, 95465-29-5; 2b, 95465-30-8; 3, 95465-31-9; 4, 95465-32-0; Fe(CO),(PPh,H),, 18399-67-2; Fe(CO)3(PCy2H)2, 95483-60-6; c~s-W(CO)~(PP~,H),, 70505-43-0; Cp2ZrCI2, 1291-32-3; Cp2TiC12,1282-40-2; Li2[Fe(C0),- (PPh2),], 95465-33-1; Li2[Fe(CO)3(PCy2)2], 95465-34-2; Li2[W(CO)4- (PPh2)2], 88930-39-6; Fe(CO),, 13463-40-6; PPh2H, 829-85-6; PCy,H, Supplementary Material Available: Table of anisotropic thermal pa- rameters, structure factors, and bond lengths and angles for l (22 pages). Ordering information is given on any current masthead page. cs2. 829-84-5. Contribution No. 3637 from the Central Research and Development Department, Experimental Station, E. I. du Pont de Nemours and Company, Wilmington, Delaware 19898 Synthesis and Molecular Structures of Diorganophosphido-Bridged Heterobimetallic Complexes R. T. BAKER,* T. H. TULIP, and S. S. WREFORD Received September 12, I984 The ’metal-containing bis(phosphine)” Cp2Hf(PEt2), reacts with Ni(C0)4, Fe2(CO)9, and (NBD)Mo(CO), to form the di- ethylphosphido-bridged heterobimetallic complexes Cp2Hf(pPEt2)2M(CO)n, where Cp = $-C5H5, NBD = norbornadiene, and M = Ni, Fe, Mo with n = 2, 3,4, respectively. The singly bridged intermediate C~,H~(PE~,)(I-PE~~)F~(CO)~ was also prepared. The molecular structure of Cp2Hf(p-PEt2)2Mo(CO),, determined by X-ray diffraction, consists of edge-shared pseudotetrahedral 16e Hf(IV) and pseudooctahedral 18e Mo(0) centers with a planar HfP,Mo bridging unit and a Hf-Mo separation of 3.400 (1) A. The complex cr stallizes in space roup Gr-P21/n (No. 14)-with four molecules in a cell of dimensions a = 13.315 (3) A, b = 18.294 (6) 1, c = 10.103 (2) 1, and zyxwvutsr 6 = 91.21 (2)O. The most widely used synthetic route’ to diorganophosphido- bridged, early-late heterobimetallic complexes involves the de- protonation of metal-coordinated secondary phosphines and re- action of the resulting anions with a transition-metal halide. An exampleZ relevant to this work is shown as follows. (1) (a) Roberts, D. A.; Geoffroy, G. L. In “Comprehensive Organometallic Chemistry”; Wilkinson, G., Stone, F. G. A., Abel, E. W., as.; Perga- mon Press: Oxford, England, 1982; Chapter 40. (b) Finke, R. G.; Gaughan, G.; Pierpont, C.; Noordik, J. H. Organometallics 1983, 2, 1481. (c) Breen, M. J.; Shulman, P. M.; Geoffroy, G. L.; Rheingold, A. L.; Fultz, W. C. Organometallics 1984,3,782. (d) Geoffroy, G. L.; Rosenberg, S.; Shulman, P. M.; Whittle, R. R. J. Am. Chem. Soc. 1984, 106, 1519. (e) Morrison, E. D.; Harley, A. D.; Marcelli, M. A.; Goeffroy, G. L.; Rheingold, A. L.; Fultz, W. C. Organometallics 1984, 3, 1407. (f) Rosenberg, S.; Whittle, R. R.; Goeffroy, G. L. J. Am. Chem. SOC. 1984, 106, 5934. (g) Jones, R. A.; Lasch, J. G.; Norman, N. C.; Stuart, A. L.; Wright, T. C.; Whittlesey, B. R. Organometallics 1984,3, 114. (h) Chandler, D. J., Jones, R. A,; Stuart, A. L.; Wright, T. C. Organometallics 1984, 3, 1830. 0020-1669/85/1324-1379$01.50/0 Et@/-70 ‘C (2) CP~MCIZ * cis-Mo(CO),(PRR’H)2 (I) 2 cquiv of n-BuLi C~~M(~-PRR’)~MO(CO)~ R = R’ = Me; R = Ph, R’ = H, SiMe3 M = Ti, Zr Cp = $-C5H5 We recently reported3 the synthesis and molecular structure of the neutral “metal-containing bis(phosphine)” CpzHf(PEt2),, which contains both single and double Hf-P bonds. We have used this and analogous complexes4to bind Ni(1,S-COD), M(PR3) (M (2) Stelzer, 0.; Unger, E. Chem. Ber. 1977, 110, 3430. Johannsen, G.; Stelzer, 0. Chem. Ber. 1977, 110, 3438. (3) Baker, R. T.; Whitney, J. F.; Wreford, S. S. Organometallics 1983, 2, 1049. 0 1985 American Chemical Society